U.S. Pat. Nos. 4,689,025 issued 8/25/87 and 4,749,374 issued 6/7/88 to Ferguson disclose a hydraulic power steering system for an outboard motor and U.S. Pat. No. 4,695,261 issued 9/22/87 to Broughton et al is directed to the location of the power take off pulley for driving the hydraulic pump for that power steering system.
That system employs the conventional teaching of using a power take off pulley attached to one end of the drive shaft to drive a hydraulic pump mounted adjacent the engine block through an endless belt.
Broughton discusses the problems associated with mounting a drive pulley directly on the crankshaft in lengthening the driveshaft. In an outboard motor, it is conventional teaching that nothing should be added to increase the height of the motor as shown by Broughton's teaching of the drive pulley radially surrounding the flywheel.
U.S. Pat. Nos. 3,282,222 issued 11/1/66 to Raufeisen; 4,229,980 issued 10/28/80 to Kingston; and 4,272,224 issued 6/9/81 to Kabele discuss the problems associated with direct coupling of a driven rotary shaft to a driving shaft.
High power outboard motors require considerable steering effort. It may be useful to provide a power steering system, using a power take off from the engine to drive a hydraulic pump. Hydraulic power may be useful for other purposes such as winches. Because the power head is so large in a high power outboard, it is difficult to find room inside the engine cover to install the necessary elements of a hydraulic steering system of the prior art including the driving pulley at the flywheel end of the crankshaft, the driven pulley, endless belt between the pulleys, the hydraulic reservoir, the hydraulic pump and the hydraulic fluid cooler. The prior art teaching is to install the hydraulic fluid cooler below the power head, the driving pulley mounted below the flywheel and surrounding the voltage generator so as to not extend the overall height of the engine, and the hydraulic pump, reservoir and driven pulley arranged vertically alongside the engine block, with the reservoir atop the pump.